BPA: Most sites may be undercounting traffic

BPA Worldwide said last month that 95% of the websites it audits may be undercounting their Web traffic. The reason: Many websites have pages that don't have JavaScript tags.
“If websites contain pages that are untagged, the potential is there for media owners to considerably underreport the amount of traffic to their sites,” Peter Black, senior VP-business development at the auditing firm, said in a statement. “ObservePoint technology allows us to uncover those pages that are not tagged and ensure sites are getting full credit in the eyes of online advertisers and media buyers.”
BPA said an average of 20% of all Web pages it analyzed went without a tag. The tags allow BPA to count unique visitors and impressions.
Online audience measurement, especially for b-to-b b media sites, is never as simple as promised. Consider the wide variations in traffic measurement figures for two Informa Business Information niche websites: BioTechniques (Biotechniques.com) and BioProcess International (Bioprocessintl.com).
In a recent study, BPA tabulated that Biotechniques.com had 64,969 unique visitors in August. Audience measurement site Compete.com had a significantly smaller figure: 11,810.
Similarly, Bioprocessintl.com had 3,800 unique visitors in August, according to BPA. Compete.com had no figures for Bioprocessintl.com, which implies that the statistical sample was not large enough.
Some of the discrepancy can be attributed to the different methodologies used by BPA and Compete.com. BPA uses a census-based system, where it determines unique visitors by consulting a site's servers. The downside of this approach is that it's difficult to gauge the demographics of visitors.
On the other hand, Compete.com and other online audience measurement companies, such as comScore, use panel-based measurement. By their nature, these panels are composed mainly of consumers and chronically undercount b-to-b traffic, observers say. However, they do provide more complete demographic information about audiences.